im using a sealed box because i made this box for a friend to put in the back of his van and he dont need it any more so he gave it back to me and it was just laying in side of my garage so i figured mine as well do some thing with it. space is not a problem its going in the back of my truck not in a blowthrough though. im using it like that so it is louder outside my truck then inside mainly to piss off people.